Effects of vitamin D administration at the beginning of lactation in dairy cows on inflammatory response and liver metabolism

This study aimed to investigate the effect of vitamin D administered 24 h after calving of dairy cows on calcium-phosphorus metabolism, carbohydrate, lipid and liver metabolism, and inflammatory response. Twenty multiparous Holstein cows were randomly assigned to the experimental (EG) and control group (CG). The EG received 5,000,000 IU vitamin D 3 (5 mL) 24 h after parturition intramuscularly, whereas the CG group received 5 mL of 0.9% NaCl. Blood samples were taken 24 h after parturition before treatments and at the 3rd, 7th, 14th, and 28th days of lactation. Serum NEFA, BHBA, haptoglobin, serum amyloid A (SAA), ceruloplasmin, calcium, phosphorus, parathormone, total protein, triglyceride, AST, and GGT were measured. In addition, total bilirubin, albumin, total cholesterol, and vitamin A concentrations were also measured to calculate liver activity index and the liver functionality index. Subclinical hypocalcemia (SCH) was observed in only one cow in the EG and five in the CG after the 3rd day postpartum. NEFA levels in the EG significantly differed on days 7, 14, and 28 when compared to vitamin D pretreatment values. However, NEFA levels in the CG differed only between day 28 postpartum and the 1st day (p < 0.05). Negative correlation was determined between vitamin D and NEFA (p < 0.01). Conversely, negative correlations were observed between calcium and NEFA, haptoglobin, SAA (p < 0.05). In conclusion, it can be suggested that vitamin D administration can prevent SCH after the 3rd day and has limited positive effects on postpartum NEFA levels.